Otoacoustic emissions but not behavioral measurements predict cochlear-nerve frequency tuning in an avian vocal-communication specialist

• DOI: 10.7554/elife.102911.2
• Publication Date: 2025-04-22T14:57:27Z
• Authors: Diana M Karosas; Leslie Gonzales; Yingxuan Wang; Christopher Bergevin; Laurel H Carney; Kenneth S Henry
• Keywords: Vocal communication; Cochlear nerve

Frequency analysis by the cochlea forms a key foundation for all subsequent auditory processing. Stimulus-frequency otoacoustic emissions (SFOAEs) are potentially powerful alternative to traditional behavioral experiments estimating cochlear tuning without invasive testing, as is necessary in humans. Which methods accurately predict remains controversial due only single animal study comparing SFOAE-based, behavioral, and frequency same species. The budgerigar ( Melopsittacus undulatus ) parakeet species with human-like sensitivity many sounds capacity mimic speech. Intriguingly, previous studies of critical bands, psychophysical curves, ratios budgerigars show that sharpness increases dramatically increasing from 1-3.5 kHz, doubling once per octave peak 3.5-4 kHz. pattern contrasts slower monotonic growth other animals, including most avian species, suggesting possible specialization budgerigars. We measured SFOAE-based cochlear-afferent budgerigars, comparison previously reported results. both increased monotonically relatively slowly higher frequencies, contrast pattern. predicted tuning, measures aligned typical patterns Divergent unlikely attributable periphery could reflect specializations central processing masked signals. Our findings highlight value SFOAEs caution against direct inference ratios.